Sizing mechanism for honing machines



April 9, 1957 J. B. KLEIN 2,787,867

sIzING MECHANISM FOR HONING MACHINES April 9, 1957 J. B. KLEIN SIZING MECHANISM FOR HONING MACHINES Filed Deo. ll, 1952 5 Sheets-Sheet 2 :1g .4 u l 62 o :e .V-w 1 92 eo 6o 3e* e 37` 1 57 6| 5g l I?? 46l 59 q L IE 59 un z '23 Yzzz ze 3J C 3G Elg 35- f/l sa E a! 35% so A 5\ l' 35" SZ 3% Qi Ei. A Y M /64- vv,l 56m f l :3o e? TJcLmeJ @.QdleLYL April 9, 1957 J. B. KLEIN CHANISM FOR HONING MACHINES SIZING ME 5 shets-Sheet 3 Filed Dec. 1l, 1952 u ff//// 1601 m )Wada/df? ((.ATTOQNEYJ NVEZNTO downed )5. CQJvLL/rn,

April 9, 1957 J. B. KLEIN 2,787,867

SIZING MECHANISM FOR HONING MACHINES Filed Dec. 11, 1952 5 Sheets-Sheet 4 FSL-4 lO 19 April 9, 1957 J. B. KLEIN sIzING MECHANISM FOR HONING MACHINES 5 Sheets-Sheet 5 Filed Deo. 11, 1952 FIIL SIZING MECHANISM FOR HONING MACHINES .lames B. Klein, Rockford, Ill., assigner to Barnes Drill Co., Rockford, lll., a corporation of Iilinois Application December 11, 1952, Serial No. 325,257

Claims. (Cl. 51-34) This invention relates generally to honing machines in which a work bore is enlarged and finished by reciprocation therein of a honing tool carried by one end of a rotary spindle and having a series of angularly spaced abrasive stones adapted to be expanded and contracted by a member movable axially through the spindle. The invention has more particular reference to the manner of terminating the honing cycle through the use of a gaging element of the so-called plug type movable into and out of feeling engagement with one end of the bore wall and adapted to enter the bore when the latter has attained a predetermined size.

The primary object is to provide an automatic plug type sizing control of the above character which is not affected in the accuracy of its measurement of the work bore by uneven wearing of the honing stones, or by run out of the hone spindle, or by the angular position in which the spindle is mounted in the honing machine.

A more detailed object is to detect the attainment of proper size of the work bore through the use of a gaging feeler or plug loosely encircling the spindle for engagement with the end of the bore wall at a plurality of angularly spaced points thereon and mounted for free transaxial floating so as to become centered automatically relative to the work bore in its initial feeling contact With the bore wall without any possibility of contact with the spindle during such centering.

Another object is to maintain the gaging plug radially separated from the rotating tool spindle by supporting the plug through the medium of a non-rotatable member carried by the reciprocable tool head.

A further object is to provide for lateral floating of the gaging plug during its feeling engagement with the work bore while holding the plug against turning at the time of such engagement and during the activation of a device for giving the up to size signal.

The invention also resides in the novel mounting of the feeler plug to achieve the desired degree of lateral float and to retain its initially centered position during that portion of subsequent reciprocations of the hone when the feeler is out of engagement with the work.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which Figures l, 2 and 3 are fragmentary front elevational views of a honing machine equipped with a size detecting mechanism embodying the novel features of the present invention.

Fig. 4 is an enlarged fragmentary cross-sectional view in a plane including the work axis and the feeler guides.

Fig. 5 is an enlarged fragmentary sectional view taken along the line 5--5 of Fig. 4.

Fig. 6 is a fragmentary sectional view taken along the line 6-6 of Fig. 4.

Figs. 7 and 8 are magnied views illustrating different conditions of engagement between the gage feeler and the work bore.

nited States Patent Fig. 9 is a fragmentary view-similar to Fig. 4.

Fig. 10 is a schematic view and wiring diagram of the honing machine and its control mechanism.

Figs. 11 and l2 are fragmentary views similar to Fig. l showing modified mountings for the feeler.

While the invention is applicable to all types of honing machines, it is shown for purposes of illustration incorporated in Va vertical honing machine in which a workpiece 10 is suitably clamped on a horizontal support 11 to locate its bore 12 in position to be honed in a succession of vertical reciprocations of a honing tool 13. The latter is carried on the lower end of a tubular spindle 14 projecting downwardly from and journaled on a rigid head 15 `accurately guided along laterally spaced rods 16a mounted in the usual way on a column 9 upstanding from the machine base. The parts of the spindle are coupled together by two hollow universal joints 17 and 18 one disposed close to and the other spaced well above the tool 13.

The spindle is driven by a motor 19 (Fig. l0) through suitable speed reducing gearing including a spline shaft 20. A hydraulic actuator 21 may be employed to move the hone into the work and then reciprocate the same therein. The honing stones 22 angularly spaced around the body 23 are disposed between the usual guides 23a and are expanded and contracted by axial shifting of cams 24 on the lower end of a rod 25 extending axially through the spindle 14. The rod may be shifted up and down by a hydraulic actuator 26.

Honing machines of the above character operate in a cycle which includes advance of the hone from a withdrawn position (Fig. l) into the Work bore, expansion of the stones 22, reciprocation of the hone back and forth through the full length of the bore until a desired size is attained, collapse of the stones, and iinally withdrawal of the hone to starting position. The present invention contemplates the provision of a mechanically acting feeler or plug 30 preferably loosely encircling the spindle 14 and mounted for reciprocation with the head 15 and for free transaxial floating so as to center itself precisely in one end of the work bore 12 during part of each reciprocation of the hone and then enter the bore when the latter has been enlarged to the desired size, such further movement constituting a signal that the honing action should be terminated. While the feeler may take various forms, it is shown as comprising a cylindrical sleeve 31 of` substantially greater internal diameter than' the spindle car- `rying at its lower end a hardened ring 32 surrounding and attached to the sleeve and having a cylindrical external surface 32a of a predetermined diameter such as to permit entry of the feeler into the bore when the latter has been enlarged to the diameter to which it is desired to finish the bore. The lower end of the ring is tapered as indicated at 33 and thus converges downwardly to a diameter smaller than the nal work bore by an amount b slightly greater than the permissible lateral iioat of the sleeve 31.

While the transaxial floating of the plug feeler may be achieved by a swivel mounting of the sleeve, the plug is mounted in the present instance for bodily lateral shifting. To this end, the sleeve is disposed within a central cylindrical opening 34 in a bracket 35 apertured at opposite ends to receive guide rods 16 which are mounted on the work xture or support 11 in front of the main guide rods 16a and extend precisely parallel to the latter. The upper end of the sleeve 31 is smaller, for example .O20-.030 of an inch, than a ring 36 fixed on the bracket. A flat external ange 37 intermediate the ends of the sleeve and axially spaced from the ring 36 is similarly spaced from the defining wall of the opening 34.

A spring 38 helically coiled around the gaging sleeve acts in compression between the ring 36 and a washer 39 latented Apr. 9, 1957` bearing against the flange 37 and urges the sleeve downwardly toward a position shown in Fig. limited by a washer 49 and an inturned flange 41 on the bracket 35 against which the sleeve ange seats. The sleeve is thus supported in the bracket for yielding axial movement and is adapted for bodily lateral oating by an amount c (Fig. 5) which is normally greater than the permissible misalinement of the work bore and the spindle axis but slightly less than the radial width b of the bevel 33. This lateral floating is however resisted by virtue of the substantial friction resulting from the engagement of the ange 37 and the washer 39 under the action of the spring 38. Thus, the position of the sleeve 31, after the latter has been centered relative to the bore by the initial feeling engagement of the bevel. 33 with the work bore 12, will be held frictionally in this precise position relative to the bracket 35 when the sleeve is lifted out of contact with the work. By proper design of the spring and positioning of its ,abutments, the friction holding force may be adjusted to the magnitude desired for maintaining the position of the gagetsleeve irrespective of the angle at which the honing spindle may be disposed in diferent machine installations.

The gaging sleeve may be mounted in various ways for movement in timed relation to the movements of the head so as to be brought into engagement with the end of the work bore wall `asthe hone approaches and recedes from the remote end of the bore. In one type of mounting shown in Fig. l, the bracket 35 has a lost motion connection with the reciprocating spindle head 15 formed by rods 42 opstanding from opposite ends of the bracket through apertures in projections 43 on the head 15. Stops 44 selectively `adjustable along the rods 42 determine the point in the upward movement of the head that the bracket 35 is picked up and the gaging sleeve thereby lifted out of contact with the end of the work bore. When the bevel 33 contacts the end of the bore 12. (see Fig. 4) during the downward stroke of the head 15, the feelcr ring 32 remains in engagement with the work, and the head and honing tool continue on down to the lower limit of the stroke of the head, the head moving on ahead of the stops 44 as shown in Fig. 3. However, if the bore 12 has by the honing action, reached the proper size, the gage ring 32 will move on with the head 15 and enter the work bore a greater distance as shown in Fig. 5. t

Such additional movement of the feeler into the work is utilized to signal complete finishing of the bore tothe proper size and preferably to interrupt the honing cycle, either immediately or after a short predetermined time delay, as by collapsing the honing tool or by withdrawing the same from the work bore without further honing action. Herein, the signal is evidenced by closure of a switch 46 disposed within a casing 47 (Fig. 5) stationarily mounted adjacent the gaging sleeve. The switch d6 is normally open but is closed and an associated normally closed switch 48 is opened by a slight depression of an actuating button 49 projecting upwardly from the casing 47. The button is engaged and depressed by an arm 51 on the gage sleeve 31 when the work bore is large enough to permit full entry ot' the ring 32 as shown in Fig. 5. The arm projects loosely through a slot 53 on the bracket 35 and herein comprises a head 52 and a spacer 53 clamped together by .a screw 54 threading into the flange 37 on the sleeve. A cross pin 55 threads through the outer end of the head 52 and may be adjusted vertically for engagement of the switch button 49 in the proper vertical position of the sleeve 31.

ln honing machines of the above character, means is provided for engagingV the hone when it becomes fully withdrawn from the work bore and holding the same approximately centered so as to insure proper entry in the next bore to be honed; This is achieved in the' present instance by two axially spaced guide surfaces 56l and 56a slightly larger in diameter than the finished work bore and positioned to receive and encircle the honing stones 23 or the stones and the guides 23El as the hone is withdrawn from the bore. Herein, the surface 56 is formed on a plate 57 detachably secured by screws 5S to a centrally apertured bracket 59 having bearings 60 at opposite ends slidable along the guide rods 16. Stops 61 ou the guide rods limit the downward movement of the bracket to a position (Fig. 4) in which the gage ring is disposed close to the upper end of the work bore. Inasmuch as the guide surface is somewhat larger than the finished diameter of the work bore, it offers no interference with the lateral oating of the gage sleeve and automatic centering thereof in the work bore as de scribed above.

Means is provided for utilizing the upward movement of the hone head 15 to raise the guide ring 57 a short distance above the workpiece in the nal withdrawal of the hone. This means comprises a lost motion connection with the gage supporting bracket 35 formed by rods 6i. upstanding from the bracket 59 and projecting slidably through the bracket`35. Nuts 63 threaded onto the upper ends of the rods 62 determine the point in the upward movement of the gage by the head 15 that the guide ring will be lifted upwardly and away from the workpiece.

The second guide surface :'56a is formed on a flange 64 turned inwardly at the lower end of the gage sleeve 31. This surface is sized to receive with ample clearance a hub 65 on the upper end of the hone body 23, the two parts being guided into telescoping relation as shown in Fig. 9 by end bevels 66 and 67. Since the transaxial floating of the sleeve 31 is limited by the amount c, the sleeve may thus be utilized to advantage to coact with the guide ring 5'7 in holding the hone against substantial lateral displacement when out of contact with the work bore. The hub 65 enters the guide flange 64 during the upper part of each honing stroke of the head 15 but owing to the clearance d (Fig. 9), the hub does not engage the surface 56- until, after completion of the honing action, the hone is fully withdrawn from the bore. Thus, the guiding action of the sleeve 31 does not interfere with its size sensing action previously described. n certain installations, the holding of the hone in the desired position while it is withdrawn from the work may be achieved by the action of only one of the guide surfaces 56 or 56a, the latter being made of the proper axial length and properly positioned axially when the Vhone is in withdrawn position.

The unique and precise action of the gaging mechanism above described in feeling of the work bore during each rcciprocation of the hone and in signalling the enlargement of the bore to the desired diameter may best be understood by following its movements during a honing cycle which may be controlled by any well known mechanism a typical form of which is shown in Fig. l0 and more fully disclosed in Patent No. 2,381,572.

At the end of each cycle, the head 15 and the hone come to rest in the withdrawn position (Fig. l) the gage sleeve 31 and the guide ring 57 being raised and the hone being disposed within the guide surfaces 56 and 56 and abovethe work bore. The several relays are then deenergized, the switch 46 is open, and the switch 74 is held open by depression of a follower 75 by a cani 76 on a disk 77 which is rocked back and forth through a ilexible two way connection 78 with the head 15. With the pump di operating, the .delivered pressure fluid is lay-passed back to the sump through a valve S2. When the startswitch 79 is closed following clamping of a ew workpiece on the support 11, the relay 7i) is energized to start the spindle drive motor l and completes a circuit through a switch 83 to energize a solenoid 84 and shift the valve 82 to interrupt the by-pass and direct pressure fluid to the valve 85 for shiftinglthe plunger of the latter to the left. Pressure fluid is thus directed to the actuator 21 to initiatedownward movement of the head 15, the gage sleeve 31 and the guide ring 57. The

motion of the latter is interrupted as it approaches the work following entry of the hone into the bore as shown in Fig. 2.

As the head moves downwardly the cam disk 77 turns clockwise allowing the switch 74 to close thus completing the holding circuit for the relay 70. As the hone reaches the lower end of its stroke, a lug 86 shifts an arm 87 and depresses the follower 88 to close a switch 39. This completes a circuit through the then closed feeler switch 48 to energize the solenoid 73 which shifts a valve 9@ to admit pressure fluid to the actuator 26 for expanding the hone. At the same time, a cam lobe 91 on the arm S7 rocks a lever 92 and through a rod 98 and an arm 99 shifts a valve 93 for reversing the direction of fluid ow to the actuator 21 thereby initiating the upward stroke of the expanded hone. As the hone reaches the upper limit of its active stroke in which the upper part of the hone is disposed abovethe bore as shown in Fig. 2, a lug 94 rocks the arm 87 reversely allowing a spring 95 to shift the valve 93 and reverse the lluid tlow to the actuator 21 thereby initiating a downward stroke of the hone.

The hone, while the stones 22 are urged outwardly by the actuator 26, is thus moved up and down through the bore and the guide ring 57 but does not contact the latter. The bracket 35 slides up and down on the guide rods 16 with the head through the upper part of the honing range but near the lower end of each down stroke the beveled nose 33 on the gage sleeve 31 encounters and partially enters the upper end of the bore wall 12 (Fig. 4). Gwing to slight differences in the location of the bore in different workpieces, the axes of the bore and the gaging surface 33 may be slightly out of precise alinement so that the initial contact between the feeler 31 and the end of the wall 12 may be on one side only of the feeler and near the lower end of the bevel as shown in full in Fig. 7. Under the action of the spring 38 and by virtue of its mounting for free lateral lloating, the sleeve shifts laterally to whatever extent may be necessary in order for the bevel 33 to seat itself fully in the end of the bore wall as is illustrated in Fig. 4 and on an exaggerated scale in phantom in Fig. 7. At this time, the bevel engages the bore wall at angularly spaced points and around the entire periphery where the wall is continuous thus becoming centered precisely with respect to the work bore.

As a result of this centering action, the sleeve 31 comes to rest, when the bore 12 is under size, in a position (Fig. 3) short of that in which the switch 46 is closed. The latter remains open'and the hone spring 3S which results in separation of the bracket n flange 41 from the sleeve flange 37 as shown in Fig. 4. This relation of the parts prevails during the remainder of each down stroke of the head and the initial part of the succeeding upstroke after which the head 15 engages the stops 44 and picks up the bracket 35 to lift the latter away from the work. In the initial part of this' movement, the bracket ilanges 36 and 41 rise and the latter flange and the washer 40 gradually come into abutment with the sleeve flange 37. Thereupon, the sleeve is lifted with the bracket out of engagement with the bore wall but, in spite of its freedom to tloat laterally, the sleeve remains precisely in the centered position determined by itspreviousseating in the bore end. This is due to the friction created by the spring force between the sleeve flange 37 and the washers 39 and 40 which tit Under its own weight, the bracket 35 may closely within the bracket holes 3 4.

in its contact with the work in the ilrst down stroke of the cycle, this position of the sleeve relative to the supporting bracket remains fixed and it is unnecessary for the sleeve to realine itself with the bore in subsequent down strokes of the head during which the successively larger diameters of the bevel 33 come into feeling engagement with the bore wall as the latter is enlarged by the honing action. Since the sleeve, when in feeling engagement with the work, is laways positioned precisely in axial alinement with the bore, it will enter the bore properly as soon as the proper amount of stock indicated at a in Fig. 8 has been honed away and the bore has been enlarged to the diameter required by the gage surface 32a. In the next down stroke of the head following the attainment of such size, the ring 32 and the sleeve 31 will move downwardly with the head 15 far enough as shown in Fig. 5 to bring the screw 55 against the switch button 49.

The resulting opening of the switch 48 deenergizes the solenoid '73 allowing the valve 90 to reverse the ilow of fluid to the actuator 26 thereby collapsing the hone. The simultaneous closure of the switch 46 completes a circuit through the then closed switch 103 'to energize a, relay 72 which closes a switch 101 and also a switch 160 for completing a holding circuit for the relay inde pendently of the switch 48.

The next upstroke of the head 15 is initiated in the usual way when t'ne lug 86 shifts the cam arm 87 to rock the lever 92 whereby to reverse the valve 93. This also closes a switch 102 thereby completing a circuit through the then closed switches 101 and 103v for energizing the solenoid 71 by which the position of the valve 93 is maintained after the lug 94 shifts the cam arm 87. Thus, the upstroke of the head is continued after opening of the feeler switch 46 thereby causing withdrawal of the head to the position shown in Fig. l. At this time, the cam 76 depresses the follower 75 thereby opening the switch 74 to deenergize the relay 70 and therefore the relay 72 and the solenoids 71 and 84. The cycle is thus interrupted with the parts in starting position.

Instead of employing the lost motion connection above described between the bracket 35 and the head 15, the two may be joined together rigidly so that the gaging sleeve moves with the head through a larger part of the latters range of movement. Such connection may, as shown in Fig. l1, be eected by threading the rods 42 directly into projections 43 on the head. With this arrangement, the gaging sleeve remains seated on the ilange 41 of the bracket during substantially the full downward stroke of the head until, near the end of this stroke, the ring 32 encounters the work bore as shown in Fig. 11. The sleeve is thus blocked by the undersize bore wall and remains in fixed centered position as the head completes its downward stroke during which the bracket flange 41 moves on ahead and away from the sleeve flange 37 as permitted by compression of the spring 33 by the ring 36.

As another alternative, the head 15 and the bracket 35 may be joined by a limited lost motion connection spring loaded in the expanding direction. As` shown in Fig. 12, the rods 42 carrying the stops 44 extend slidably through the projections 43 on the head 15 and are urged downwardly by springs 105 acting in compression be tween the projections and collars 106 fixed to the rods below the projections. The combined force of the springs 105 plus the weight of the bracket 35 is substantially less than the force of the spring 33 so that the connection remains expanded as shown in Fig. l2 with the sleeve 31 seated on the flange 41 until the sleeve encounters the work. Then in the continued downward movement the springs 105 are compressed until the projections 43 encounter spacers 107 after which the spring 38 is com Thus, after. .thev centered position of the sleeve is once determined, usually',v

averse? prs-sed as described above in the final part of the down stroke.

` It will be., apparent that with gaging feeler 31 mounted as described above the entry of the gage sleeve into the work to close the switch 46 is timed precisely with the enlargement of the work bore to the desired diameter. This is for the reason that the gage sleeve is brought into feeling Aengagement with the bore Wall during each down stroke of the bore and is positioned so accurately in alinement with the bore that it will enter the latter immediately when the proper diameter is attained. Such positioning of the sleeve is produced in the tirst or at least one of the early down strokes of the cycle and then is carefully retained in the subsequent strokes even though the feeler is retracted out of engagement with the work during the latter part of each upstroke. This is due to the friction force applied continuously to the sleeve 'flange 37 in each position to which the sleeve is moved by lateral floating to adapt itself initially to a given work bore. This resisting force although yieldable in character is nevertheless of suicient magnitude to hold the feeler position when the feeler is out of control by the bore wall.

The size detecting action above described is achieved by engagement of the gage member directly with the wall defining the work bore. As a result, the accuracy of the measurement is in no way affected by uneven wearing off of the honing stones, by run out or lateral wobbling of the drive spindle, or other slight inaccuracies in the mounting of the head or the gage supporting bracket.

l claim as my invention:

vl. The combination of, a honing machine for honing a work bore having a work support, a reciprocable tool head, a rotary jointed spindle thereon carrying a hone having a hub on its spindle end, a gage sleeve loosely surrounding said spindle and separated therefrom by a continuous annular space, said sleeve having a tapered end engageable with the end of the bore wall when the latter is undersize but adapted to enter the bore when the latter is honed to the proper size, means on said head supporting said member for independent but limited floating movement transversely of said spindle and also for axial movement along the spindle into and out of engagement with the Work as the hone approaches and is retracted from the end of its inward stroke, an internal surface on said gage sleeve being adapted to receive and guide said hone hub when the hone is withdrawn from the work, a guide ring encircling the spindle axis and disposed between said sleeve and the work support, said ring having an internal surface of a diameter slightly larger than the gaging diameter of said sleeve, and supporting means for said ring having a lost motion connection with said head and operable to allow said ring to remain adjacent the work bore during the honing thereof and to retract the'ring away from the work when the hone is withdrawn therefrom.

2. The combination of, a honing machine for honing a work bore having a work support, a reciprocable tool head, a rotary jointed spindle thereon carrying a hone having a hub on its spindle end, a gage sleeve loosely surrounding said spindle and separated therefrom by a continuous annular clearance space, said sleeve having a tapered end engageable with the end of the bore wall when the latter is undersize but adapted to enter the bore when the latter is honed to the proper size, means on said head supporting said member for independent but limited heating movement transversely of said spindle and also for axial movement along the spindle into and out of engagement with the worl: as the hone approaches and is rctracted from the ond of its inward stroke, and an internal surface on said gage sleeve adapted to receive and guide said hone hub when the hone is withdrawn from the work.

3. The combination of, a honing machine for'honing a work `bore having a work support, a reciprocable tool head, a 'rotary jointed spindle thereon carrying a hone having a hub lon its spindle end, a gage sleeve loosely surrounding said spindle and separated therefrom by a continuous clearance space, said sleeve having a tapered end cngageable with the end of the bore wall when the latter is undersize but adapted to enter the bore when the latter is honed to the proper size, means on said head supporting said member for independent but limited iloating movement ltransversely of said spindle and also for axial movement along the spindle into and out of engagement with the work as the hone approaches and is retracted from the end of its inward stroke, an internal surface on said gage sleeve adapted to receive and guide said hone hub when the hone is withdrawn from the work, a guide ring encircling the spindle axis and dis posed between said sleeve and the work support, said ring having an internal 'surface of a diameter slightly larger than the gaging diameter of said sleeve, and means supporting said guide ring adjacent the work support.

4. in a honing machine for enlarging a work bore to a predetermined diameter, the combination of, a ro tary honing tool having radially expandable abrading elements, a frame, a support for said tool mounted on said frame for movement along the tool axis to reciprocate the tool within the work bore and thereby hone the latter, an annular gage plug encircling said tool axis and having adjacent the vtool a bevel surface which flares away from the tool to an external gaging surface equal to said predetermined diameter, means movable with said support and mounting Vsaid gage plug for movement along said axis and also for limited floating relative to the support Vin a direction transversely of the axis, an abutment movable with said support and engageable with said gage plug to limit the axial movement thereof toward said tool but to permit said bevel surface to enter into and dwell in feeling engagement with the end of the bore during the final part of each advance of said tool, said abutment reengaging the gage plug and moving the same away from the work during the reverse stroke of said tool and support, spring means urging said gage plug toward and against said abutment to create friction between the engaging surfaces of Vthe two for holding the gage plug against lateral shifting relative to said support while the gage plug is out of Contact with the work whereby to maintain the retracted 'gage plug in the transaxial position attained in its previous feeling engagement with the work, and means for signalling the entry of said gage plug into the work bore beyond said bevel surface when the bore has been honed to said predetermined diameter.

5. In a honing machine for enlarging a work bore to a predetermined diameter, the combination of. a rotary honing tool, a frame, a support for said tool mounted on said frame for movement along the tool axis to reciprocate the tool within the Work bore and thereby hone the latter, a gage encircling said tool axis and having between the tool and said support a bevel surface which flares away from the tool to an external gaging surface equal to said predetermined diameter, means on said support mounting said gage for limited movement along aid axis and also for limited floating relative to the support in a direction transversely of theaxis whereby to permit said bevel surface to enter into and dwell in feeling engagement with the end of said bore wall during the final part of each advance of said tool but to retract the'gage away from the work during the reverse stroke of said support, spring means urging said gage axially toward said tool, surfaces on said gage and its support yieldably urged together and coacting while the gage is out of contact with the work to hold the gage in a predetermined transaxial position and prevent floating of the gage laterally relative to said support, and means for signalling the entry vof said gage into the work bore beyond said bevel surface when the bore has been honed to -said predetermined diameter.

6. In a honing machine for enlarging the bore of a supported workpiece to a desired size, the combination of, a head reciprocable back and forth along the axis of said bore, a rotary spindle projecting from said head along said axis and carrying a honing tool for enlarging said bore, a gaging plug in the form of a ring surrounding said spindle between said tool and said head and having an interi-or larger than the spindle by an amount sufficient to provide a continuous clearance between the two at all times, said plug being normally urged toward said tool and having near its end a gage surface of said desired size and a bevel beyond such surface converging toward said tool and acting to center itself and the plug on said axis on coming into abutment with the end of said bore but to enter the bore when the latter has been enlarged to the diameter of said gage surface, ya nonrotatable member carried by and reciprocable with said head and surrounding said plug, and coacting means on said member and the exterior of said plug axially spaced from said gage surface and supporting the plug out of Contact with said spindle and for movement along said axis relative to said spindle and said head and also for lateral oating of the plug and gage surface transversely of said axis by an amount suicient to permitautomatic centering of said bevel in said bore.

7. A honing machine as defined in claim 6 in which said member comprising a bracket projecting from said head along said spindle and connected to the head for reciprocation therewith so as to support said plug independently of any contact with said spindle.

8. A honing machine as dened in claim 6 in which said member is a bracket projecting from said head and having a lost motion connection therewith permitting of independent movement of the bracket relative to the head along said spindle axis.

9. A honing machine as defined in claim 6 in which said plug is urged axially by a spring and said coacting means supporting the plug includes mating surfaces formed on and extending around the exterior of the plug and the interior of said member. f

10. A honing machine as dened in claim 9 in which said coacting means supports said mating surfaces for relative movement along said axis and such surfaces separate from each other during the final advance of said head following abutment `of said bevel with said bore end.

11. A honing machine as defined in claim 9 in which said spring, when said sleeve is retracted out of abutment with said bore end, urges said mating surfaces together under suticient pressure to frictionally maintain the centered lateral position of said beveled end and gaging surface.

12. A honing machine as defined in claim 9 in which said mating surfaces are the opposed sides of radial flanges formed on the plug and member respectively and normally abutting each other under the action of said spring.

13. In a honing machine for enlarging the bore of a supported workpiece to a desired size, the combination of, a tool head reciprocable back and forth along the axis of said bore, a rotary spindle projecting from said head along said axis and carrying at its end a honing tool for enlarging said bore, a gaging plug in the form of a ring surrounding said spindle between said tool and said head and having a beveled end coacting with the bore end to center the plug automatically on said axis and an adjacent gaging surface adapted to enter the bore when the latter is of said desired size, the interior of said ring being radially separated at all times from said spindle by a subf stantial clearance, said plug being urged axially along said axis toward said tool, means for mounting said ring independently of and at all times out of contact with said spindle including a nonrotatable member carried by and reciprocable with said head and at least partially surrounding said plug, said mounting means supporting the plug for movement back and forth with the head along said axis and also for limited lateral floating transversely of said axis to permit of said automatic centering, an abutment acting to limit the movement of said plug toward said tool at an axial position in which said bevel end comes into abutment with said bore end short of the end of the forward stroke of said head, and means for sensing the entry of said plug into said bore as the latter attains said desired size.

14. In a honing machine for enlarging the bore of a supported workpiece to a desired size, the combination of, a tool head reciprocable back and forth along the axis of said bore, a rotary spindle projecting from said head along said axis and carrying a honing tool for enlarging said bore, a gaging plug in the form of a ring surrounding said spindle between said tool and said head and hav- .ing a beveled end coacting with the bore end to center the plug automatically on said axis, said plug having adjacent the bevel a gaging surface adapted to enter the bore when the latter is of said desired size, said plug being normally urged axially along said axis toward said tool, means positively holding said plug against turning about said axis during recipro'cation of said head and rotation of said spindle and mounting the plug for movement back and forth with the head and spindle along said axis, said mounting means also supporting said plug for limited lateral oating transversely of said axis to permit of said automatic centering, an abutment acting to limit said axial urging of said plug to an axial position such that said bevel end comes into abutment with said bore end short of the end of the forward stroke of said head, and means coacting with a nonrotatable part of said plug to sense entry of said plug into said bore as the latter attains said desired size, said positive holding means preventing relatlve turning between the bore and said beveled end at the time of and during abutment of the two.

15. A honing machine as defined in claim 14 in which said sensing means includes a device stationarily mounted adjacent said gage plug and activated during entry of said plug 1n a bore of said desired size, said device coacting with a part movable back and forth with said plug and at all times maintained by said holding means in a predetermined angular position of alinement with said device.

References Cited in the le of this patent UNITED STATES PATENTS 1,831,915 Hurm Nov. 17, 1931 1,934,858 Isom Nov. 14, 1933 2,252,809 Kline Aug. 19, 1941 2,581,601 Peden Ian. 8, 1952 2,631,414 Muehling Mar. 17, 1953 FOREIGN PATENTS 613,962 Great Britain Dec. 7, 1948 

